If you don’t plan to smash your piñata soon, make sure you protect it from insects. The flour and water papier mâché mix is an all-you-can-eat buffet for insects, and if you keep your piñata for too long, bugs will eventually turn it into a breeding ground. I have safely kept unprotected piñatas indoors for two years, and I know someone who safely kept one for six years. On the other hand, when I left some piñatas unprotected in my garage, bugs got into them within weeks.
If I’m keeping a piñata for a while and it’s not on display, I close it up in a large plastic bag along with a few cedar disks to discourage curious insects. The cedar disks won’t keep the bugs out forever, though. I’ve also been told that adding a few tablespoons of salt to each cup of papier mâché will help keep insects away.